Cutter blade



`June 26, 1928. v 1,674,838

E. F. RAYMOND. CUTTER BLADE Filed March 1Y0, 1925 INVENToR. Z2/Ward fag/mam BY MJ A TT ORNEYS.

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CUTTER BLDE.

Application led March 10, 1925. Serial No. 14,430.

This invention relates to a. rotary drilling tool employing blades, and pertains especially to the blade structure. Cutting of the formation through which such types of tools d are advanced is performed by the shearing action of the blades. rlhe primary object of the present invention is to provide a blade for such tools which will oier a maximum of cutting edge of such conformation as to eciently bite into and cut the formation. Another object of this invention is to provide a blade which is interchangeable' thereby permitting removal and replacement9 making it unnecessary by reason thereof to perform blacksmith work on the job. ln addition to the broader objects of this invention, there are certain details of structure, whereby a strong, durable, and economical rotary drill bit is obtained.

These obiects are obtained by means of the embodiment of my invention illustrated in the accompanying drawing, in which:

Fig. 1 is an amai section through the lower end of a drill; Fig. 2 is a section as seen on the line 2-2 of Fig. 1; and Fig. 3

is a perspective view of a blade.

Referring more particularly 4to the drawing, the blade is shown as incorporated in a rotary core barrel having a bcdy. The body 3o is of tubular form and is split or divided diametrically to provide halves 5 and 5. Adjacent the lower end the body is enlarged in diameter, tapered and threaded as indicated by 6. At the bottom oi the threaded ortion the body is further expanded as inicated by 7, ending in a cylindrical portion 8. f

`Mounted upon the body is a sleeve 9 which vides a Water space 10. Communicating with the water space 10 and leading through the body are water courses 11. The bore of the bod orming the core retaining part is enlarge in diameter at the bottom to receive a trimming ring, and key recesses ex- 5o tending longitudinally thereof.

The trimming ring is splijt axially to form halves 12 and 12'.. The lower edge of the ring is provided with cutting teeth 13 serving to trim the core. Each half of the ring has a key lug as indicated by 14 and 14. The key lugs seat in corresponding key recesses in the body thereby retaining the ring in position when the halves of the body are locked together. rlhe ring also serves to hold the blades of the tool in position.

The body of the tool is provided with slots to receive the blades. These slots have walls converging radially outwardly and diverging upwardly. Each blade is of 'quadrilateral form and tapers in an axial direction the convergence being toward the cutting edge. The wall cutting face provided with cutting -edge 15 of the blade is fluted. The 70 face provided with the lower cutting edge of the blade is likewise luted, the cutting edge beingrounded as indicated by 16. As seen from an inspection of Fig. 3, the nose' or forward cutting edge of each blade is iiuted and the rear edge straight so as to be flush with the valleys of the iutes, thereby providing'clearance for cuttings. It will be noted that a blade and its recess are so shaped that when the. blade is inserted in position, it cannot be moved .radially outwardly by reason of it being thicker at the back than at the front. It cannot be moved downwardly for the reason that it is thicker at the top than at the bottom. The trimming ring retains the blade from moving radially inwardly.

ln the use of the tool, cores may be removed by removing the sleeve 9 to unlock the halves of the body and also the halves of the trimming ring, thereby laying the bore of the tool open without disturbance of the core therein. Opening the tool in the same manner gives access to thefblades so that they may be removed and replaced.

The shape of the cutting edge is such as to break up the formation and act more eilicientIy. The lineal length of cutting edge for each blade is much greater than with the edges sloping back to straight ltrailing edges, 10 straight edge. The result is a. tool which the side faces of said plate body converging has a, high degree of eciency in cutting. toward the corner formed by the intersection What I claim is: of said edges.

5 An insertable blade for a rotary boring In witness that I claim the foregoing I tool comprising a plate body of quadrihave hereunto subscribed my name this 3rd l5 lateral form having a, wall trimming face day of March, 1925. ip

intersecting a, hole-advancing face, said faces being corrugated to form iluted cutting EDWARD F. RAYMOND. 

